Lost on Kyni 9 (Troubleshooters 4)

Tony (nearly 13) and his girl cousin, Bea (111/2), are sent with a Negotiator to the planet Kyni 9, whose leader wants to buy ten thousand fenceposts. Ten thousand fenceposts! But, if she wasn't going to build a fence, what was she going to do with them? (story length 52 700 words)